Frassetto Fabio, Coraggia Stefano, Miotti Paolo, Poletto Luca
National Council for Research of Italy- Institute of Photonics and Nanotechnologies (CNR-IFN), via Trasea 7, 35131-Padova, Italy.
Opt Express. 2013 Jul 29;21(15):18290-303. doi: 10.1364/OE.21.018290.
The design and realization of a stigmatic grazing-incidence instrument for space applications to solar imaging spectroscopy is presented. We propose an optical layout in which imaging and spectral capabilities are decoupled by the use of crossed cylindrical mirrors. The design consists of a double telescope and a spectrograph: telescope I consists of a single cylindrical mirror with parabolic section, focusing the radiation on the entrance slit of the spectrograph in the spectral dispersion plane; telescope II consists of two cylindrical mirrors with aspherical section in Wolter configuration focusing the radiation on the spectrograph focal plane in the direction perpendicular to the spectral dispersion plane; the spectrograph consists of a grazing-incidence spherical variable-line-spaced grating with flat-field properties. Telescope II is crossed with respect to the grating and telescope I, i.e., is mounted with its tangential planes coincident with the grating equatorial plane, to decouple spectral and spatial focusing properties. The spectral resolution is preserved also for off-axis angles. The instrument that has been realized operates in the 4-26 nm spectral range and has a field of view of 0.5 deg to image the full Sun disk.
介绍了一种用于太阳成像光谱学空间应用的消像散掠入射仪器的设计与实现。我们提出了一种光学布局，其中通过使用交叉柱面镜将成像和光谱功能解耦。该设计由双望远镜和光谱仪组成：望远镜I由一个具有抛物面截面的单柱面镜组成，将辐射聚焦在光谱仪在光谱色散平面上的入射狭缝处；望远镜II由两个呈沃尔特配置的具有非球面截面的柱面镜组成，将辐射聚焦在光谱仪垂直于光谱色散平面方向的焦平面上；光谱仪由具有平场特性的掠入射球面变线距光栅组成。望远镜II相对于光栅和望远镜I交叉，即其切平面与光栅赤道平面重合安装，以解耦光谱和空间聚焦特性。对于离轴角度，光谱分辨率也得以保持。已实现的该仪器在4 - 26纳米光谱范围内工作，视场为0.5度，用于对整个太阳盘面成像。
